Cut up a 1/2 slab of ribs and brown the spare ribs in a bit of any olive oil or crisco
This browning is optional
Cover the ribs well with water, add bay leaves, garlic, several peppercorns and the diced onion.
Cook the ribs until very soft.
I always use a pressure cooker since it's a time saver. But this isn't necessary.
When the ribs are cooked, remove the meat from the rib bone and cut into pieces and put back into the pot. Leave the "ribs water" and add the sauerkraut and also some shredded fresh cabbage. The fresh is optional but really stretches the soup in case you don't have a lot of kraut on hand and it tastes good, too!
Add the can of diced tomatoes and some sliced mushrooms. If your lucky enough to have some wild mushrooms around, they're wonderful in any "kapusta" dish. Add more water if necessary for the soup consistency you like.
This soup can be made from any cut of fresh pork that you have on hand. It's best to use something that has a bone. So, even if all you have is a pork chop and a little bit of kraut in the fridge you can make a small pot of soup for yourself.
One special old time favorite is to have some chilled, whole boiled potatoes on the side.
The hot soup and cold potatoes complement each other.
I realize this is a loosly described recipe. But kapusta soup is something you can't screw up. The strong flavor of the kraut takes care of any sins along the way.